GOP presidential candidate Herman Cain was on the defensive Monday after allegations surfaced of improper behavior at one of his former jobs.

Cain has launched from the bottom of the pack, to the top of the polls in recent weeks -- but with frontrunner status comes frontrunner scrutiny.

"When you have the best plan on the table, expect to be attacked," Cain said whiled defending his 999 tax plan.

Now, the accusations have gotten more personal.

A report published Sunday on Politico.com suggested Cain was accused of sexual harassment by two unidentified women while leading the National Restaurant Association in the 1990s.

According to Politico, the women in question were paid to leave the association and to keep quiet. No sources are named in the report.

In a statement Sunday to The Associated Press, Cain's campaign disputed the claims.

"I'm not going to comment about two people who you won't tell me who they are, okay?" Cain told CBS News when questioned about the report.

Monday, Cain's campaign switched into full damage control mode, with the candidate keeping his schedule in Washington for the day.

First, Cain gave a taxes and fiscal policy speech at the American Enterprise Institute, where he didn't take questions about the accusations.

On Fox News, Cain said he was aware of an accusation while he worked for the National Restaurant Association, but he didn't know about a settlement.

"I've never sexually harassed anyone," Cain said. "Yes, I was falsely accused while I was at the National Restaurant Association. And I say 'falsely' because it turned out, after the investigation, to be baseless."

Cain then faced a room full of reporters at the National Press Club.

"When the charges were brought, as the leader of the organization, I recused myself and allowed my general counsel and my human resource officer to deal with the situation," Cain explained.

His campaign accused the media of making a personal attack.

Despite the accusations, Cain seems to be refusing to let this change his personality or campaign style.

To prove that point, Cain showed his faith and love of gospel music to the press club -- ending his appearance by singing, "'Amazing Grace' will always be my song of praise, for it was grace that brought me liberty."

David Brody

CBN News Chief Political Correspondent

David Brody is an Emmy Award-winning veteran news journalist who has interviewed many prominent national figures during his career of nearly 25 years. Currently, David covers the White House and interviews national newsmakers across the country. Follow David on Twitter @TheBrodyFile and "like" him at Facebook.com/TheBrodyFile.